Bibcode
Oliveira, R. A. P.; Souza, S. O.; Kerber, L. O.; Barbuy, B.; Ortolani, S.; Piotto, G.; Nardiello, D.; Pérez-Villegas, A.; Maia, F. F. S.; Bica, E.; Cassisi, S.; D'Antona, F.; Lagioia, E. P.; Libralato, M.; Milone, A. P.; Anderson, J.; Aparicio, A.; Bedin, L. R.; Brown, T. M.; King, I. R.; Marino, A. F.; Pietrinferni, A.; Renzini, A.; Sarajedini, A.; van der Marel, R.; Vesperini, E.
Bibliographical reference
The Astrophysical Journal
Advertised on:
3
2020
Journal
Citations
26
Refereed citations
25
Description
In the present work we analyzed seven globular clusters (GCs) selected from their location in the Galactic bulge and with metallicity values in the range -1.30 ≲ [Fe/H] ≲ -0.50. The aim of this work is first to derive cluster ages assuming single stellar populations and second to identify the stars from first (1G) and second generations (2G) from the main sequence, subgiant, and red giant branches, and to derive their age differences. Based on a combination of UV and optical filters used in this project, we apply the Gaussian mixture models to distinguish the multiple stellar populations. Applying statistical isochrone fitting, we derive self-consistent ages, distances, metallicities, and reddening values for the sample clusters. An average age of 12.3 ± 0.4 Gyr was obtained both using DSED and BaSTI (accounting atomic diffusion effects) isochrones, without a clear distinction between the moderately metal-poor and the more metal-rich bulge clusters, except for NGC 6717 and the inner halo NGC 6362 with ∼13.5 Gyr. We derived a weighted mean age difference between the multiple populations hosted by each GC of 41 ± 170 Myr adopting canonical He abundances; whereas for higher He in 2G stars, this difference reduces to 17 ± 170 Myr, but with individual uncertainties of 500 Myr.
Related projects
Milky Way and Nearby Galaxies
The general aim of the project is to research the structure, evolutionary history and formation of galaxies through the study of their resolved stellar populations, both from photometry and spectroscopy. The group research concentrates in the most nearby objects, namely the Local Group galaxies including the Milky Way and M33 under the hypothesis
Martín
López Corredoira